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arXiv 2006.00477astro-ph.GA
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GRB061007、GRB061121、GRB080605、GRB090926B、GRB080207和GRB070521宿主星系观测光谱的分析。Ha和SFR趋势

Analysis of the spectra observed from GRB061007, GRB061121, GRB080605, GRB090926B, GRB080207 and GRB070521 host galaxies. Ha and SFR trends

Marcella Contini

摘要:

本文通过模拟最近观测到的线状和连续谱,计算了一个红移范围为1<z<2.1的长伽玛暴(LGRB)宿主星系的物理条件和N/H和O/H相对丰度。在更广泛的红移范围z<3内,这些结果与先前计算的LGRB宿主星系一致。我们分析恒星形成率(SFR)内的LGRB主机的基础上的Ha通量。它们与本地低光度星暴(SB)星系,个别HII地区的本地星系以及LGRB宿主星系在中等和相对较高的红移进行了比较。增强的SFR在附近星系的HII区域内的解释是一个相对较高的填充因子,其特征是“个别区域”,而不是“整个星系”,这是通常所提出的意见。星系中的碎片物质来自祖先的合并。我们检验了被捕获到尘埃颗粒的冰帽中的O_2和N_2分子的冰的形态转变释放是否可以解释整个红移过程中的N/O比。我们已经发现,通过模拟光谱计算出的冲击速度足够高,足以完全摧毁冰幔。因此,防止二次氮形成是解释z<1时低N/O比的有效假设。SFR随z增加的趋势大致类似于N/O的趋势。

英文摘要:

We calculate the physical conditions and the N/H and O/H relative abundances for a sample of long GRB (LGRB) host galaxies in the redshift range 1<z<2.1 by modelling recently observed line and continuum spectra. The results are consistent with those previously calculated for LGRB host galaxies throughout a more extended redshift range z<3. We analyse star formation rates (SFR) within the LGRB hosts on the basis of the Ha fluxes. They are compared with those of local low-luminosity starburst (SB) galaxies, individual HII regions in local galaxies as well as LGRB host galaxies at intermediate and relatively high redshifts. The enhanced SFR in the HII regions within nearby galaxies is explained by a relatively high filling factor which characterizes "individual regions" rather than "entire galaxies" which are generally presented by the observations. The fragmented matter in the galaxies derives from progenitor merging. We check whether the release by the morphological transformations of ice of the O_2 and N_2 molecules trapped into the ice mantles of dust grains could explain the N/O ratios throughout the redshift. We have found that shock velocities calculated by modelling the spectra are high enough to completely destroy the ice mantles. Therefore, the prevention of secondary nitrogen formation is a valid hypothesis to explain the low N/O ratios at z<1. The SFR trend increasing with z is roughly similar to that of N/O.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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